Apparatus for making radiographs.



E. GATESI APPARATUS- FOR rM AK|NG RADIOGRAPHS.

' (Application filed Sept. 26, 1-393.)

(No Model.)

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In: uomus PETERS co. Pnmaumm WASHINGTON, c

UNITED STAT S" PATENT 7 OFFICE.

ELMER GATES, OF CHEVY CHASE, MARYLAND, ASSIGNOR TO THEODORE J. MAYER, OFWASHINGTON, DISTRICT OF COLUMBIA.

APPARATUS F0RIMAKINGIVRADIIOGRAPHSI.

SPECIFICATION forming part of Letters Patent No. 653,383, dated July 10,1900.

Application filed September 26, 1898. Serial No. 691,909. N model.)

To ctZZ whom it may concern:

Be it known that I, ELMER GATES, a citizen" of the United States,residing at Chevy Chase, in the county of Montgomery and State ofMaryland, have invented certain new and useful Improvements in Apparatusfor Making Radiographs, of which the following is a specification,reference being had therein to the accompanying drawings.

It is generally accepted as a fact that in taking skiagraphs orradiographs there are conditions as to the penetrative power or themaximum efficiency of X-rays which can only be attained bya carefulmanipulation of the apparatus, varying its handling somewhat in eachcase of use according to the exhaustion of the tube, the potentialdifference between cathode and anode portions of the tube, whether thespark be produced by astatic machine or by an induction-coil,atmospheric and other conditions, which necessitate the use ofconsiderable time in making the adj ustments and in bringing theapparatus from a state of rest into a condition of highest usefulnessfor the particular work in hand at that particular time, and when thisresult has been accomplished there should beno change or interruption ofthe operation until the sensitive plate has been exposed to the actionof the X-rays at their maximum of efficiency as thus produced for therequisite period of.

time; but with the appliances heretofore employed such preferable modeof procedure is impossible, it being the practice to stop the machinejust as the'said maximum of; efficiency has been attained to permit theplate in its holder or carrier to be brought into the room, placed inthe apparatus, and adjusted, after which the apparatus is started andagain brought up to its maximum of efficiency,where it is maintained forsuch space of time as will suffice to produce the best result which ispossible under the interruption which has occurred. While it isgenerally believed that better skiagraphs or radiographs could be madein casethe machine were not stopped to permit the' plate in its holderto be brought into the room, placed in the apparatus, and adjusted, yetwith plate-holders as heretofore constructed it has beenfound advisableto thusstop the machine in order to avoid fogging the plate while it isthus being handled in the open air of the room while the X-rays arebeing given off by the tube.

The object of my invention is to producea skiagraph or radiograph byexposing the plate or'other sensitive surface to the action of X- raysof the desired maximum intensity maintained by a continuous operation ofthe machine unbroken by a stoppage, as above explained, and also withoutthe plate being present in the apparatus during the time when theabove-indicated production of X-rays of the desired efiective intensityare being generated or produced as contradistinguished from the ordinarymethod or process of sub jecting said plate or sensitive surface to theaction of X-rays which are of less than the desired effective intensity,are gradually brought up to such effectiveness, and are then maintainedat such maximum for a period of time.

In carrying out my invention, I propose to protect the sensitive surfacefrom the action of the X-rays'until the latter have been de veloped upto the desired eifective'intensity, and then expose said sensitivesurface to the action of such effective X-rays. In carrying out myinvention I propose to keep the plate at such a distance from theapparatus and under the proper conditions as will practically insurethat it shall not be affected by the rayswhile they are'being developed,and then, without stopping the machine, bring in the plate in a holder"which is impervious, or at least practically impervious, to such rays,place the/plate in proper position to receive the X-rays and removetherefrom a portion of the impervious holder, and subject said sensitivesurface to the action of X-rays of the maximum or desired intensity ofeffectiveness for the requisite period of time. In carrying out thispart of my invention I prefer to employ a holder made of some materialwhich is impervious to X-rays-such' as, for instance, lead prepared inthin sheets, with upon one side'or upon both sidesthinsheet-iron tosupport the lead and protect it against accidental injury ordisplacementbut good results may be attained by the use of fluoresedgesto the finished article.

cent or tungsten screen, upon which said rays impinge with an innercomposite sheet of material, part of which is impervious to energy-wavesof such length as will traverse such screen, so that by the con jointoperation of the fluorescent screen and the inner opaque sheet thesensitive surface is protected from the action of the X-rays for therequired period of time; but after the plate-holder has been placed inthe apparatus and adjusted the opaque surface can be withdrawn and thesensitive surface exposed to the action of the X-rays of the desiredmaximum intensity and the skiagraph taken.

Having thus set forth in general terms the character of my invention, Iwill explain one mode which I have adopted for carrying it into effect.

Figure 1 is a central longitudinal section of a plate-holder made inaccordance with my invention. Fig. 2 is a central transverse section ofthe same plate. Fig. 3 is a central longitudinal section of amodification. Fig. 4 is a transverse section of Fig. 3. Fig. 5 is acentral longitudinal section of another modification. Fig. 6 is atransverse section of Fig. 5. Fig. '7 is a top plan view, on a reducedscale, of Fig. 1.

Like references indicate similarparts in all the figures.

Referring particularly to Figs. 1, 2, and 7, A A B B represent,respectively, the side bars and the end bars of a rectangular frame,made preferably of wood, as is customary in plate-holders. As shown inthe cross-sections,the bars A A have upon their upper faces ledges orshoulders a a a a, and the end bar B has similar ones I) I), while theopposite end bar 13 is thinner than B, being practically of thethickness of B at its inner edge, so that the upper faces of bar B andthe ledges or shoulders a a b are in plane.

The back of the holder is indicated generally by C, and it is composedof a series of layers or thin films alternately disposed of some of thesubstances which are most nearly impervious to the X-rays, among whichmaterials I recommend lead and iron as being very useful, and I preferto make the outer and inner sheets of iron, because of its being so muchharder and stiffer than lead, and therefore better adapted for thesurfaces which will be exposed to the wear and tear incident tohandling. For convenience in illustration I have shown the back as composed of only three layers, an inner one d of iron, a middle one 6 oflead, and an outer one fof iron; but I wish it understood that inpractice I prefer to use a larger number of alternately-disposed sheets,making them, particularly the inner ones, very thin, thus avoiding undueweight of the holder, and making the outer and inner layers inonecontinuous sheet doubled back upon itself will facilitate confining theintermediate sheets in proper place and also the making of smooth Asindicated at the other edges, the outer layer may be turned inward overthe intermediate ones and soldered to the inner one, thereby avoidingrough edges. Upon three sides of the frame this composite sheet iscontinued around over the outer edge surface and inward upon the frontsurface and preferably a short distance beyond the shoulders or ledges aa I), thus forming narrow recesses or grooves between the compositesheet and the end and side bar surfaces a a b to receive the edges ofthe slide to be described.

A A B are ribs of either metal or wood,

' with screws a? a U passing through the ribs and the composite sheetinto the frame-bars to confine the parts in place, the corners of theframe proper being held by glue and pins or screws, as is customary.

G represents the sensitive plateor surface, which may be of any usual orapproved sort, and need not therefore be described in detail. In frontof the sensitive surface there is or may be a tungsten screen II or itsequivalent.

The slide I consists of a composite sheet similar to that of which theback is made, as is indicated by the same letters d cf, with an expandedend or bar I to handle it by, and its width and thickness are such as tofacilitate its being inserted if the grooves formed for its receptionbetween the ledges or shoulders a a b and the projecting edges of thecomposite sheet, as has been explained.

J is a sheet or plate of material which is pervious or transparent tothe X-rays, but is impervious, or nearly so, to the ordinary lightraysand is disposed upon the surfaces a a I) just in front of the slide, sothat the object of which the skiagraph is to be made may be placed inproper position against this sheet J without interfering with thewithdrawal of the slide after the X-rays have been brought up to therequired efliciency, and I prefer that the flexibility of J be such thatwhen the slide has been withdrawn the said object can be pressed towardthe sensitive surface, so that there shall be only the thickness of theflexible sheet between the object and said surface, or the tungstenscreen, when the latter is used. Thus this sheet J serves as a IIO Slideguard or' protector, insuring absolute non-contact of the slide with theobject placed in front of it.

I recommend a thin sheet of manila paper of proper size to fit closelywithin the walls of the recess when frictional contact will ordinarilyhold J in place; but as means for fu r-' ther securing it in positionscrews b may be inserted through the composite sheet and J or suitablepoints.

In the construction shown in Figs. 3 and 4 the parts are the same as Ihave described above, except that in place of a guard orprotectorsecured between the ledges or shoulders a a b I propose toemploy one in the shape of an envelop or bag-like jacket is, whichsurrounds the entire holder frame and back, except that it is open atone side to receive the slide and is preferablyheld in place by means ofthe ribs A A B As it is sometimes desirable to take a skiagraph of anobject of much greater size in one or both directions than the sensitiveplate and of such character that it is desirable to omit from the holderthe parts which project beyond or in front of said sensitive surface, Ihave devised the modification shown in Figs. 5 and 6, where the groovesfor the reception of the edges of the slide are formedin the side bars AAof the frame and are dovetailed in cross-section to fit thecorrespondingly-shaped edges of the slide, which are turned inward atpractically right angles to the body of the slide, as at t' i, (see Fig.7,) and the bentover edges of the composite sheet are secured inrecesses a a) b so that after the slide has been withdrawn the bag-likeenvelop or guard K can lie in a plane across the sensitive surface,orthe tungsten screen,when the latter is used, and also upon the adjacentparts of the holder, as will be readily understood without furtherexplanation.

Instead of using a series of plates or even a single plate of materialwhich is impervious or nearlyimpervious to the X-rays, I may employ aslide made of some material which will convert the X-rays into waves ofa materially-different length and place behind that a sheet of materialwhich will intercept such longer waves, and thereby accomplish sub-,

stantially the same result.

What I claim is 1. A plate-holder for a sensitive surface comprising aremovable slide made wholly or in part of a material that is imperviousor nearly so to X-rays.

2. A plate-holder for a sensitive surface, comprising a slide made inwhole or in part of material which is impervious, or nearly impervious,to X-rays, and a guard or protector in front of the slide adapted toprevent contact of the slide with the object to be represented on thesensitive surface, substantially as set forth.

3. A plate-holder for a sensitive surface comprising, in combination, aguard that is pervious to X-rays but impervious to lightrays, and aslide which is impervious to X- rays.

4. A plate-holder for use with an X-ray apparatus comprising, incombination, a plate sensitive to such rays, a slide impervious thereto,and a guard that is imprevious to light-rays but pervious to X-rays.

In testimony whereof I affix my signature in presence of two witnesses.

ELMER GATES.

